DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY

BOTTOM SEDIMENT ALONG OIL SPILL TRAJECTORY IN PRINCE WILLIAM SOUND AND ALONG KENAI PENINSULA, ALASKA

Edited by Paul R. Carlson and Erk Reirnnitz

Chapter E. Preliminary report on benthic foraminifers from Prince William Sound, Alaska

Paula J. Quinterno US. Geological Survey Menlo Park, California

Open-File Report 90-39-E

This report ispeliminary and has not been reviewed for conformity with US. Geological Survey editorial s t a n d d s or with the North American Stratigraphic Code. Any use of trade, product, or finn

nmes is for descriptive purposes only and does not imply tndorsement of the U.S. Gov~nment.

PRELIMINARY REPORT ON BENTHIC FORAMINIFERS FROM PRINCE WILLIAM SOUND, ALASKA

Paula J. Quinterno

INTRODUcrION

A U.S. Geological Survey cruise (F5-89-PW) was conducted aboard the R/V FAR- NELLA from May 11 to May 15, 1989 to assess the effects of the March 24, 1989 Exxon VALDEZ oil spill on near-surface sediment (Carlson and Reimnitz, this volume). Station loca- tions are shown in figures l and 2. Foraminifera1 faunas and sediment types are described in the Appendix.

Subsamples were taken from the upper 2 cm of 18 box cores, presewed in 70% ethanol, and stained with rose Bengal while onboard ship in order to recognize foraminifers that were living at the time of collection. Samples were washed over a 0.063mm mesh sieve to remove the silt and clay; the residue was air dried and dry sieved using a 0.150mm mesh sieve; the <0.150mm midue was stored in a labelled vial; when necessary, the 9.150mm portion was split with a microsplitter to obtain appmximately 300 benthic foraminifers. AU specimens in the split fraction were sorted, identified, and counted. Percentages were calculated for "total" benthic taxa (stained + unstained) by dividing the number of specimens (stained + unstained) of each taxon by the total number of specimens in that sample and multiplying by 100. The percentage of "live" (stained) taxa was obtained by dividing the number of stained specimens of each taxon by the total (stained + unstained) number of specimens in that sample and multi- plying by 100.

Ninety-one benthic taxa were recognized and are listed in Tables 1, 2, and 3 as percen- tage of total benthic foraminifers. Both calcareous and agglutinated benthic foraminifers are present. Live (stained) foraminifera1 taxa are listed in Table 2. Table 3 lists taxa and their abundances as percentage of total benthic foraminifers in 4 samples (unstained) taken from >2 cm depth in 3 box cores.

Planktonic foraminifers are present in all the samples, but not abundant. In addition, because there are no surface tow samples for comparison with present day planktonics, they will not be discussed further in this report.

RESULTS Benthic foraminifera1 distribution in Prince William Sound is related to sediment type.

The foraminifera1 faunas present in the coarsest sediment (Box Cores 1, 17B, an8 18) are dom- inated by species of Cassidulina californica, C. limbata. C. tortwsa, and Cibicides lobatulur (Figs. 1. 2). Previous workers in the Gulf of Alaska have found similar faunas associated with coarse sediments. Bergen and O'Neil (1979) designated a "gold" fauna dominated by high percentages of Cussidulina and Cibicides, associated with coarse sediment. Echols and Annen- ttrout (1980) reported a similar group of species in the Gulf of Alaska which occurred only on shelly, gravelly substrates. They called this the Cassidulina californica Fauna. Other report. of similar faunas associated with coarse sediment include Todd and Low (1967) and Quinterno et al., (1980) in the Gulf of Alaska; Boettcher, (1967) off Oregon; and Bandy (1953). Blake

(1976), and Zalesny (1959) off California. Low oxygen foraminiferal faunas are frequently found in fine-grained sediments beneath

highly productive oceanic waters. An association of species typical of low oxygen environ- ments (4.5 mVL of 02) is present in very fine grained sediments of Prince William Sound. It is best developed at Stations 7 and 8, but is also present at Stations 9 and 10 (Fig. 1). Abun- dant diatoms, an indication of high productivity, occur in sediments at these sites. The benthic foraminifera1 fauna is dominated by Bolivirta pseudobeyrichi, Uvigerina juncea, and Globobu- limina spp. Poag (1981, 1985) found that high abundances of Brizalirta (Bolivina) and Uviger- inu in the Gulf of Mexico correlated with an oxygen minimum and with high amounts of organic carbon. A stained specimen of Bolivina pseuhbeyrichi is figured on the title page @age 1) of this repdrt.

The significance of the low oxygen faunas in the Prince William Sound samples is uncer- tain, but it should be noted that this fauna is best developed closest to the oil spill (Station 7). Unfortunately, no baseline studies of foraminifera1 distribution had been done before the spill; therefore, the composition of previous foraminiferal faunas and any changes since the spill are unknown. Only 4 downcore samples (>2cm) were available for this report, and give only a general idea of what the past faunas were. Rates of sediment accumulation are not known for this area, so we do not know when the various layers were deposited. Furthemore, Corliss (1985) has found some species living (stained) as deep as 15 crn in deep sea cores, so some of the foraminifers in the Prince William Sound samples from the 2-8 an intervals may have been living at the time of collection, but this cannot be known since stain was only added to sam- ples from the upper 2 cm of the cores. Table 4 compares the abundances of low oxygen taxa in surface samples 7B, 7C, and 9A with abundances at various depths in cores 7C, 9A, and 9B. Surface samples have greater abundances of the 3 low oxygen taxa than do subsurface samples. Two of these genera, Bolivina and Uvigerina have also been correlated with high amounts of organic matter in sediment (Poag, 1981, 1985). The greater abundance of the low oxygen (and high organic carbon) fauna in the surface samples might be an indication that the oil spill has affected the benthic foraminifers by altering their environment. However, the observed faunal change is slight and is probably the result of natural environmental processes,

Although no oil was found in the seafloor sediments, the benthic organisms could be affected by changes in the water column caused by the spill. These changes, however, would not necessarily be detrimental to all species of foraminifers. Bandy, Ingle and Resig (1965a.b) in studies of foraminifers in surface sediments around sewage outfalls off the Los Angeles area found that not all species of foraminifers are adversely affected by pollutants. In fact, the greatest number of living foraminifers were found downcurrent from the outfall. In the Prince William Sound samples, the highest percentages of live foraminifers are found at stations in the vicinity of the spill (Table 2). Live specimens of Bolivina pseudobeyrichi make up 174, 8%, 13% and 6% of the total benthic foraminifera1 faunas at Stations 7 (B and C), 8A, 9A, and 10C, respectively. Live percentages of Uvigerina juncea are 6%. 396, 11 %, 8%. and 11% at Stations 7B, 7C, 8A, 9A, and IOC mpectively. Live pemntages of Gbbubuliminu spp. make up 8%, 9% and 4% at stations 7B, 7C, and JOC respectively. It is possible that these species are opportunistic, that is, they are able to tolerate environments that other organisms cannot: therefore, they thrive due to lack of competition.

CONCLUSIONS Distribution pattern of benthic foraminifers in the surface sediments of Prince William

Sound show a relationship to sediment size and also to the distance from the VALDEZ oil spill. Although relationships can be seen, there is not enough evidence to know for certain what the controlling factors are. Good baseline studies are necessary for valid interpre-tations and, unfortunately, these studies are lacking in Prince William Sound. Future studies should include seasonal sampling of the water column for plankton and the seafloor sediment (both surficial and downcore) and staining of sediment samples from 0-15cm to determine the spatial and temporal distribution of benthic foraminifers.

ACKNOWLEDGMENTS

I thank Kristen McDougall (U.S. Geological Survey) for her review of the manuscript and Brad Carkin (U.S. Geological Suwey) for his technical support.

REFERENCES

Bandy, O.L., 1953, Ecology and paleoecology of some California Foraminifera. Part I. The frequency distribution of Recent Foraminifera off California: Journal of Paleontol- ogy, v. 27, no. 2, p. 161-182.

, Ingle, J.C. and Resig, J.M., 1965a, Foraminiferal trends, Hyperion outfall, California: Limnology and Oceanography, v. 10, p. 314-332.

, 1965b. Modification of foraminifera1 distribution by the Orange County outfall, Califor- nia: Ocean Science and Ocean Engineering, p. 55-76.

Bergen, F.W. and O'Neil, P., 1979, Distribution of Holocene foraminifera in the Gulf of Alaska: Journal of Paleontology, v, 53, no. 6, p. 1267-1292.

Blake, G. H., 1976, The distribution of benthic foraminifera in the outer Califomia Continental Borderland and its relationship to Pleistocene marl biofacies: Unpub. Master's Thesis, University of Southern Califomia, 143p.

Boettcher, R.S., 1967, Foraminifera1 trends of the central Oregon shelE Unpub. Master's Thesis, Oregon State University, 134p.

Corliss, B. H., 1985, Microhabitats of benthic foraminifera within deep-sea sediments: Nature, V. 314, p, 435-438.

Echols, R. J. and h e n t r o u t , J.M., 1980, Holocene foraminifera1 distribution patterns on the shelf and slope, Yakataga-Yakutat area northern Gulf of Alaska, in Field, M.E. and others, eds., Quaternary Depositional Environments of the Pacific Coast. Pacific Coast Paleogeography Symposium 4: Society of Economic Paleontologists and Mineralogists, Pacific Section, Los Angeles, p. 281-303.

Poag, C.W., 1981, Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico: Marine Sci- ence International, Woods Hole, MA, 174p.

, 1985, Benthic foraminifera as indicators of potential petroleum sources, in Perkins, B.F., and Martin, G.B., Habitat of Oil and Gas in the Gulf Coast: Society of Economic Pahntologista and Mineralogists Foundation, Gulf Coast Section, Fourth Annual Research Conference, Proceedings, Houston, TX, June 1983, p. 275-284.

Quintemo, P., Carlson, P.R., and Molnia, B.F., 1980, Benthic foraminifers from the eastern Gulf of Alaska, in Field, M.E. and others, eds., Quaternary Depositional Environ- ments of the Pacific Coast. Pacific Coast Patwgeography Symposium 4: Society of Economic Paleontologists and Mineralogists, Pacific Section, Los Angeles, p. 13-21.

Todd, Ruth, and Low, Doris, 1967, Recent Foraminifera from the Gulf of Alaska and Southeastern Alaska: U.S. Geol. Survey Prof. Paper 573-A, p. A1-A46.

Zalesny, E.R., 1959, Foraminiferal ecology of Santa Monica Bay, California: Micropaleontol- ogy, v. 5, no. 1, p. 101-126.

APPENDIX. Description of Sediment Type and Foraminifera1 Faunas The station location information and the description of the sediments that follow are taken

from Carlson and Reimnitz (this volume).

I have listed below the most abundant species and their relative fnquency percentages in each sample. These data are also shown on Figures 1 and 2.

Station 1, Box Core I -Location: At the mouth of Montague Strait -Water depth= 1 6thn -Sediment type: Gray diarnict containing abundant angular pebbles and cobbles up to 10 cm in diameter. 60% sand, granules, cobbles. -"Washed sedimentM= (the portion of sample ~maining on the 0.063mm sieve after wet sieving to eliminate fines and concentrate foraminifers): Detrital minerals, shell fragments, and a little glauconite (?). -Fauna: Some test. fresh, some very poorly preserved; many fragments. Cassidulina limbata =29%, Elphidium clavatum var. =21%, Cibicides lobatulus =17%, Cassidulina californica =14%. -Clayey worm tubes, euphausid(?), pelecypod, sponge spicules, echinoderm parts, brachiopod fragments, fish tooth(?), -Other: One conifer needle.

Station 2, Box Core 2A -Location: In Montague Strait -Water depth=246m. -Sediment type: mottled medium gray clayey silt; no laminations, no bedding. -Washed sediment: <O.lSOmm=mostly detrital minerals. >0.1S0mm=rnostly detrital with some clay, worm tubes, shell fragment and minor diatoms. -Fauna: Diverse, >50 species. Cibicides lobatulus =IS%, Angulogerina angulosa =6%, Astro- nonion gallowayi =6%, Trochammina spp. =6% -Rarely some pyrite in forarn tests. -Ostracodes, bryozoan fragments, echinoderm fmgrnents, pelecypods, sponge spicules, ptero- pods(?).

Station 3, Box Core 3A -&ation: East of Knight Island. -Water depth=268m. -Sediment type: Very soft, non-stratified gray silty clay with a 1 cm thick layer of soupy brown material at the surface.

-

-Washed sediment: <0.150=mostly diatoms. >0.1SOmrn=mostly clay aggregates. -Fauna: Adercotryma glomerata = 1296, Eggerella udvena = 12%, Uvigerina juncea =9%, Bolivina pseudobeyrichi =7%. -Sponge spicules, worm tube, euphausids(?), ostracodes (rare). -Other: Diatoms are abundant.

Ststion 4, Box Core 4A -Location: In Snug Harbor, Naked Island. -Water depth=125m. -Sediment type.: Very soft gray, slightly shelly, mottled mud. -Washed sediment: <0.150mm=mostly diatoms. >0.150mm=mostly clay aggregates. -Fauna: Nonionella pulchella =17%, Eggerella advena =9%, Florilus labraabricus =8%. -0stracodes; small pelecypods abundant.

Station 5, Box Core SA -Location: South of Naked Island -Water Depth=215m. -Sediment type: Gray silty clay covered by a thin (lcm thick) layer of brown soupy ooze-like mud. -Washed sediment: <0.150mm=mostly diatoms. >0.150mrn=mostly clay aggregates. -Fauna: Uvigerina juncea =24%, Ishndiella norcrossi =9%, Elphidiurn clavatum var. =8%. -Ostracodes, worm tubes, pelecypods, euphausids (?), sponge spicules, Dentalia (?).

Station 7 -Location: About 1.5 n.mi. southwest of Bligh Reef, along the trajectory of the oil from the point of spill. -Sediment type: Very soupy gray, very fine mud; all tops disturbed.

--BOX COR 7B -Water Depth: 398m -Washed sediment: <O.ISOmm=Nearly equal amounts of diatoms and clay aggregates; some detrital minerals. >0.150mm=mostly clay aggregates and clayey worm tubes. -Fauna: Bolivina pseudobeyrichi =23%, Uvigen'na juncea -174, Globobulimina spp. =11%, Flori11~~ labradoricur =9%, Islandiella norcrossi =9%. -2 very large Hyperammina sp. aff. H. arenaria. -Clayey worm tubes, pelecypods, ostracodes (rare), euphausids (?), echinoderm parts, fecal pel- lets.

--Box Core 7C --Water Depth: 394m -Washed sediment: <0.150rnrn=mostly diatoms. >0.150mm=diatoms and clay aggregates. -Fauna: Bolivina pseudobeyrichi =36%, Uvigerina juncea = 1 3 4, Globobulimina = 12% Florilus labradoricur =9%, Haplophragmoides bradyi =9%. -Ostracodes, fish vertebrae (?), echinoderm parts. -Other. Some plant rnate1ia.L

Station 8, Box Core 8A -Location: North of Naked Island. -Water depth=480m. -Sediment Type: Bmwn, very soupy mud. -Washed sediment: <0.150mm=diatoms and clay aggregates. >0.150mm=slightly more clay aggregates than diatoms.

-Fauna: Uvigerim juncea =38%, Bolivina pseudobeyrichi =16%, Haplophragmoides bradyi 4%. -Radiolarians (trace), ostracodes, pelecypods, insect wing, worm tubes (?), echinoderm parts. -Other: Some plant material

Station 9, Box Core 9A -Location: West of Naked Island in the deepest part of Prince William Sound. -Water Depth: 755m. -Sediment Type: One to two cm-thick layer of brown watery mud overlying very soft gray mud. -Washed sediment: <O.lSOmm=About equal amounts of clay aggregates and diatoms. M. 150mm=mostly clay aggregates some containing stained foraminifers such as Uvigerina. -Fauna: Bolivina pseudobeyrichi =20%, Uvigerina juncea =20%, Haplophragmoides bradyi =14%. -Other: Ostracodes (trace).

Station 10, Box Core 10A -Location: North of Perry Island. -Water Depth: 340m. -Sediment type: Very soft light gray silty clay. -Washed sediment: <0.150mm=more diatoms than clay aggregates. >0.150rnm=clay aggre- gates more abundant than diatoms. -Fauna: Uvigerina juncea =2 1%. Haplolphragmoides bradyi = 108, Bolivina pseudobeyrichi =9%. -Other: Ostracodes.

Station 11, Box Core 11A -Location: Southwest of Perry Island -Water Depth: .4oom. -Sediment type: Firm, light gray clayey diamict with angular pebbles up to 4 m in diameter overlain by brownish, watery sediment layer 0.5m thick with numerous tube worms. -Washed sediment: <0.150mm=mostly detrital sediment. >O. lSOmm=Networks of sponge spi- cules make up much of the coarse portion of the sediment; much detrital minerals and some clay. -Fauna: Trmhumrnina spp.=19%, R e o p k scorpiurus =18%, Reophax spp.=13%, Uvigerina juncea =11%. -A few very large agglutinated foraminifers Nodosinurn gaussicum (?I . -Sponge spicules (net-like) very abundant, ostracodes, worms, brittle star, echinoderm parts. -Other Pine needle.

Station 12, Box Core 12A -Location: In Herring Bay; chosen because of the reports of abundant oil on the beach and intertidal zone. -Water depth: 183m. -Sediment type: Thin, brown, soupy layer underlain by gray homogenous mud. Several large bumws (3-4 cm diameter, up to 30 cm deep) Wed with very watery, soupy mud. -Washed sediment: <0.150mm=mostly diatoms. >O. 15Omm=mostly clay aggregates; diatoms and clayey worm tubes common. -Fauna: Uvigeriw juncea =19%, Islandiella norcrossi =11%, Globobulimina spp. =9%, Ader- cotryma g lornerata =8%. -Fecal pellets.

Station 13, Box COE 13B -Location: Central part of Knight Island Passage -Water Depth: 389m. -Sediment type: Brown mud over gray diarnict. -Washed sediment: <0.150mrn=mostly diatoms. >0.150rnm= Large masses of net-like sponge spicules; detrital minerals and clay aggregates. -Fauna: Angulogerina angulosa =13%, Uvigerina juncea =13%, Reophax subfusifomis =9%, Cibicides mckannai =8%, Reophax scorpiurus =8%.

Station 15, Box Core 15A -Location: South of Knight Island Island. -Water Depth: 240m. -Sediment type: Upper 2 cm is oxidized sand which is underlain by 5 cm of reduced sand and pebbles; the lower part of the core (10cm) is a diamict with pebbles, cobbles, some shell frag- ment. and a large isolated pod of mud. -Washed sediment: <0.150mm=mostly detrital minerals. >0.150mrn=mostly detrital minerals; many large agglutinaw foraminifers. -Fauna: Cribrostomoides crassimargo = 16% Adercotryma glomerata = 1446, Rhabdammina spp.=12%. -Sponge spicules.

Station 16 -Location: About 40km southwest of Seward. -Water depth: 277111. -Sediment type: Homogenous silty clay.

-Box Core 16A -Washed sediment: d.l50mm=mostly diatoms. >0.150mm=clay aggregates slightly more abundant than diatoms. -Fauna: Nonionella pulchella =20%, Ghbobulimina spp.= 14%. Florilus labradoricus = 13%. Ostracodes, fish tooth, echinoderm parts, euphausid (?). -Other Diatoms very abundant.

-BOX COE 16B: -Washed sediment: <0.150mrn=mostly diatoms. >0.150mm=clay aggregates more abundant than diatoms; some forams in the clay, many stained; some detrital minerals. -Fauna: Nonionella pulchella =2 1 56, Globobulimina spp.= 1 8 %, Florilus labradoricus = 15%. -0stracodes (trace), worm tubes, echinoderm parts. -Other: Diatoms very abundant.

Station 17, Box Core 17B -Location: About 75km southwest of Seward. -Water Depth: 115m. -Sediment type: Homogenous muddy coarse sand, brownish surface with tube worms and a brittle star. -Washed sediment: <0.150mm=detrital minerals and shell fragments. >0.150mm=mostly shell fragments; some detrital minerals and clay aggregates; a little glauconite (?). -Fauna: Cassidulina tortuosa =39%, C. californica =26%, Cibici&s lobatulus =23%. -Some specimens are fresh-looking, others are dull, broken andlor Wed with glauconite. -Other: Pelwypods, gastropods, worms, ostracods, echinoderm parts.

Station 18, Box Core 18 -Location: About 50km west of Station 16. -Water depth: 95m. -Sediment type: A thin layer of oxidized ooze at the surface overlying gravelly, sandy mud with scattered shells. -Washed sediment: <0.150rnm=detrital minerals abundant; some diatoms. >O.lSOmm=detrital minerals abundant; some diatoms. -Fauna: Angulogerina ~ g u l o s a =33%, Cassidulina lirnbata =18%, Cibicides Iobatulus =lo%, Cassidulim californica =9%. -0stracodes (trace), pelecypods, sponge spicules, worms, fibrous brachiopod fragments. -Other: Diatoms.

EXPLANATION OF SYMBOLS AND ABBREVIATIONS ON FIGURES 1 AND 2.

"Goldwor Cassidulincr californica fauna:

Cassidulina californica z.v.., li""'l Cassidufinu limbata

Low Oxygen Fauna:

Globobulimina spp.

Uvigerincr juncea

Abbreviations of other taxa on Rgures 1 and 2:

Non.pul.= Nonionella pulchella

Tro.spp= Trwhanunina spp.

Bar graph

F i g u ~ 1. Location map for samples taken in Prince William Sound during cruise F5-89-PW. Bar graphs show percentage of total benthic foraminifers for the most abundant species at each site. See page 13 for explanation of symbols and abbreviations.

C)<<*q:;g_Q Q < = C q o Q ~ q = N F E -

, N M L n r ~ m * x

SPECIES Adercotryma glomerata 1 2 1 2 4 6 I 1 2 4 3 3 8 1 2 1 ~ 4 g x 2

Table 1. Percentage distribution of Total (live + dead) species in surface samples. x =<I% - =absent

Table 1 continued

SAMPLE NUMBER

4 4 m 4 < f Q m a < ~ ~ 4 < 0 = n e s q f , f $ e P a @ O - - -

- N A * ~ K X ~ X X X j r c

X x o ~ ~ a Q Q ~ ~ ~ ~ ~ ~ ~ ~ o ~ , O $ ~ a ~ p r ~ @ f l ~ ~ ~ m a m a a ~

E. v i m - 2 2 3 ) - X - - 3 - 6 2 1 2 1 - 1

R. fusifmis R. scorpiurus X

2 2 - - - - X - X Z - - - - ? l S S r 8

1 - 1 X 8 I 2 X e X X

I - -

1

4 u 4 ; 4 ~ _ 4 4 q m a -

4 < < @ r m $ - - 4 m 3 m F * P 5 4 9 5 G

% - - N X

, ~ o ~ A ~ o ~ ~ ~ ; a * ~ ~ ~ ~ ~

& Z a s $ p m p $ a a @ ~ r n m r n ; $ SPEC l ES R. subfusiformis - > ( - - - - - - - I 3 2 9 - x 1 - 1 : 3 I

other miliollids - I x ~ ~ ~ x ~ - ( / I - ( - I 1 - 1 1 - - - r l 1 0 \ * 4 3 3 - Q I ~ - - r n N - " W ~ ~ c u v , O - v ,

Numberofrpecimcns fi 9 5 5 F 2 a $ $ 9 C f $ $ -

Table 1 continued

Table 2. Percentage distribution of Live species (calculated as percentage of the Total number of specimens) in surface samples.

x =<I% - =absent

4 4 4 4 P d 4 < d ~ < a < < @ & r n - N n T m r r m ~ " ~ F ~ Q ~ X - - -

x X x * . . o o . o o , * ~ " . : : * . ~ , " ~ X x * X %

SPECIES $ $ @ m @ m m d d c ~ m a @ @ @ & m m E. vitrea - X I 2 X - X - _ - 2 - 2 - I I I - X

( R. scorpiurus

Table 2 continued

Table 2 continued

AMPLE NUMBER

L) 2 r n < 4 m F 9 4 4 4 5 @ ~ ~ 4 0 4 _ ~ ~ 9 9 c m

- N ~ T y e a m ; - , X x d ~ x x X d K x g % x x X o o o o o o o o ~ o Q o O o O o o O

SPEC l ES a @ @ @ @ @ @ a @ a a E l @ @ a r n * @ R. subfusifomis - x - - - - - - - X I I I - X I - x

Subreophax aduncus Textularia spp. Triloculina trihcdra -

- - - - - -

+

T. spp. Uvigerina I-LL~ juncea U. senticosa Valvulineria sp. other calcareous other agglutinated other miliollids

x

- _ _ -

- - - -

I

-

-

I

Number of specimens

3

- X X -

2 - @ b m + ~ $ ~ g $ ~ % ' z ~ * d m ~ m

2 ~ d e e t - r n ~ = - Z ? $ & $ - -

-

- X - - - -

e

- + - - _

- - _

-------- 2 9

3 - -

- - - _ - - - _ - _

-

- _ -

Y - - -

-

- x

6 3 -

-

- - - - x - / - - - -

-

- x - - - -

- - - j r j - 3

l l I 8 1 1

-

-

x _ _ _ _ _ -

- - _ _ _ -

- - - -

+

3

I X - x X I - - - -

_ I .

*

-

----- 1

23 - _ _ - _ _ _ _ -

- 2 - - -

- _

- - f

I I

-

1

- -

iT'/r 2 3

I -

_ - - _

- - - -

7--

- X x - - - - - +

-. - - -

-

T

SAMPLE NUMBER E 5 5 ; : A w

u a P m $ 2

X X r C X

SPECIES O O ~ O

a m m m Adercotryma glomerata

Table 3. Percentage of Total (live + dead) species in subsurface samples. x =<l% -=absent

E

N CI a

E. v i m 2 3 - -

Table 3 continued

E E B g S 2 q 3 m & W & e

c\l

0 4 < m c - 0 . 0 . 0 -

r c r l A X 0 0 0 0

a m m a

R. subfusiformis 4 - 9 -

blumbtr of specimens

Table 3 continued

Table 4. Percentage of low oxygen species in surface and subsurface samples. x =<I%

E 5 E u

a " $ 5 p b e ' ; @ e r g g A

0 0 0 b $ ~ 8 r n $ r n r n -

Bolivina pseudobeyrichi

Globobdimina spp.

Uvigerina juncea

5% of low oxygen species in each sample

23

11

17

51

36 19

12 16

13 12

61 47

20 13 4

x 0 1

20 16 29

40 29 33

0

0

25

25